What are GTIN, MPN, and brand in Merchant Center?
GTIN (Global Trade Item Number), MPN (Manufacturer Part Number), and brand are product identifiers that help Google match products to queries and catalog entries. GTINs (barcodes) are issued by GS1 and are globally unique for each product. MPN is the code the manufacturer assigns to the product. Brand identifies the company that made the product, which may differ from the seller.
When is a GTIN required in Merchant Center?
GTINs are required for products that have them. Branded products that are sold by multiple retailers generally have assigned GTINs. If your product has a barcode, submit the GTIN. Google cross-references submitted GTINs against the GS1 database. Products with known GTINs that are submitted without them may receive reduced eligibility or lower Shopping quality scores compared to competitors who do include the GTIN.
What is identifier_exists and when should it be used?
identifier_exists is an attribute that signals to Merchant Center whether a product has a GTIN, MPN, or brand. It should only be set to false for products that genuinely do not have these identifiers: custom-made items, handmade goods, vintage products, or private-label products manufactured without a barcode. Setting identifier_exists to false for branded products that have GTINs is incorrect and reduces product quality.
Should you use fake or placeholder GTIN values?
No. Submitting placeholder values (such as all zeros, or a repeated sequence like 0000000000000) is treated as an error by Merchant Center and will cause disapprovals. If a product does not have a GTIN, use identifier_exists false instead of fabricating a value. Fabricated GTINs also fail validation against the GS1 database.
How should private-label products be handled?
Private-label products manufactured for a retailer typically do not have assigned GTINs. Set identifier_exists to false and submit the brand name (your brand, not a manufacturer brand), and an MPN if you have assigned one internally. This is the correct configuration for custom-manufactured or white-label products and avoids the disapprovals associated with missing GTIN errors on products that never had one.
| Identifier | What It Means | When It Is Required | Common Mistake |
|---|---|---|---|
| GTIN | Global Trade Item Number (barcode) | Required for branded products that have one | Not submitted for products that have a barcode |
| MPN | Manufacturer Part Number | Required when no GTIN exists for branded products | Retailer SKU submitted instead of manufacturer MPN |
| Brand | Product manufacturer or brand owner | Always required unless genuinely unbranded | Reseller name submitted instead of product brand |
| identifier_exists | Signal that product has no identifiers | Only for custom, handmade, vintage, private-label | Set to false for branded products to avoid GTIN requirement |
Identify affected products
- –Check Diagnostics tab for GTIN, MPN, and identifier errors
- –Filter products by disapproval reason to find identifier-related issues
- –Export the affected product list for review
For products with GTINs available
- –Locate the GTIN from the product barcode or manufacturer documentation
- –Verify the GTIN validates correctly (standard formats: UPC-12, EAN-13, ISBN-13)
- –Update the feed with the correct GTIN value
- –Remove any identifier_exists false attribute if present
For private-label or custom products
- –Confirm the product has no assigned GTIN (check with manufacturer)
- –Set identifier_exists to false
- –Submit your brand name for the brand attribute
- –Submit an internal product code as MPN if you have one
For MPN issues
- –Confirm MPN is the manufacturer code, not your internal SKU
- –Contact the manufacturer if MPN is unknown for their product
- –If no MPN is available and no GTIN exists, use identifier_exists false
For the full feed review process, check our guide to Merchant Center feed audits.